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Diffstat (limited to 'macros/cell2sos.sci')
| -rw-r--r-- | macros/cell2sos.sci | 197 |
1 files changed, 106 insertions, 91 deletions
diff --git a/macros/cell2sos.sci b/macros/cell2sos.sci index 39402b3..7cd657d 100644 --- a/macros/cell2sos.sci +++ b/macros/cell2sos.sci @@ -1,95 +1,110 @@ -function [s,g] = cell2sos(c) -//Converts a cell array to a second order section matrix -//Calling Sequences -//s=cell2sos(c) -//[s,g]=cell2sos(c) -//Parameters -//c -//A cell array -//g -//The scalar gain -//Description -//s=cell2sos(c) converts a a cell array c = { {B1},{A1}, {B2},{A2}, ... {BL},{AL}} -//to an L-by-6 second-order-section matrix s given by: -// s = [B1 A1 -// B2 A2 -// ... -// BL AL] -//numerator vector Bi and denominator vector Ai contains the coefficients of a -//linear or quadratic polynomial. If the polynomial is linear, the coefficients -//zero-padded on the right. -//[s,g]=cell2sos(c) estimates the gain from the leading term of the cell array -//c={ {[g1,g2]},{B1},{A1}, {B2},{A2}, ... {BL},{AL}} to give g=g1/g2 as the gain -//Example -//c=cell(1,5); -// -//c(1,1).entries=[2, 1]; -// -//c(1,2).entries=rand(1,3); -// -//c(1,3).entries=rand(1,3); -// -//c(1,4).entries=rand(1,3); -// -//c(1,5).entries=rand(1,3); -// -// c = -// column 1 to 3 -// -//![2,1] [0.2113249,0.7560439,0.0002211] [0.3303271,0.6653811,0.6283918] ! -// -// column 4 to 5 -// -//![0.8497452,0.6857310,0.8782165] [0.0683740,0.5608486,0.6623569] ! -//[s,g]=cell2sos(c); -//s = -// -// column 1 to 5 -// -// 0.2113249 0.7560439 0.0002211 0.3303271 0.6653811 -// 0.8497452 0.6857310 0.8782165 0.0683740 0.5608486 -// -// column 6 -// -// 0.6283918 -// 0.6623569 -// -//g = -// -// 2. -//Author -//Ankur Mallick - if(argn(2)~=1) then - error("Wrong number of input arguments"); - end +// Copyright (C) 2018 - IIT Bombay - FOSSEE +// This file must be used under the terms of the CeCILL. +// This source file is licensed as described in the file COPYING, which +// you should have received as part of this distribution. The terms +// are also available at +// http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt +// Author: Abinash Singh Under FOSSEE Internship +// Modifieded by: Abinash Singh Under FOSSEE Internship +// Last Modified : 3 Feb 2024 +// Organization: FOSSEE, IIT Bombay +// Email: toolbox@scilab.in +/* +Calling Sequence : + sos = cell2sos(cll) + [sos,g] = cell2sos(cll) +Description + sos = cell2sos(cll) generates a matrix sos containing the coefficients of the filter system described by the second-order section cell array cll. + [sos,g] = cell2sos(cll) also returns the scale gain g. + + Second-order section cell-array representation, specified as a cell array. + +Input Argument: + For a filter system with L sections, specify 'cll' using this structure: + + * Cell array with L elements — For unity-gain filter systems. Each element of the cell + array corresponds to a second-order section. The kth cell array element of 'cll' + + cll{k} = {[b_0k b_1k b_2k] [1 a_1k a_2k]} + + contains the coefficients from the kth second-order-section of the filter system H(z): + + H(z) = product(k=1 to L) H_k(z) + = product(k=1 to L) (b_0k + b_1k*z^(-1) + b_2k*z^(-2))/(1 + a_1k*z^(-1) + a_2k*z^(-2)) + + * Cell array with L+1 elements — If the gain of the filter system is different from 1. + The first element of 'cll' contains the system gains at the numerator (g_n) and at + the denominator (g_d). Then, the function appends each element of the cell array for + the corresponding second-order section. + + The first and the k+1th cell array element of 'cll' - L=prod(size(c)); - for i=1:L - if(type(c(i))~=17) - error('Cell contents must themselves be cell objects'); + cll{1} = {g_n g_d} + cll{k+1} = {[b_0k b_1k b_2k] [1 a_1k a_2k]} + + contain the system gain and the coefficients from the kth second-order section of + the filter system H(z), respectively, such that: + + H(z) = (g_n/g_d) * product(k=1 to L) H_k(z) + = (g_n/g_d) * product(k=1 to L) (b_0k + b_1k*z^(-1) + b_2k*z^(-2))/(1 + a_1k*z^(-1) + a_2k*z^(-2)) + +Output Argument: + Second-order section representation, returned as an L-by-6 matrix, where L is the + number of second-order sections. The matrix + + sos = [b_01 b_11 b_21 1 a_11 a_21] + [b_02 b_12 b_22 1 a_12 a_22] + [ ⋮ ⋮ ⋮ ⋮ ⋮ ⋮ ] + [b_0L b_1L b_2L 1 a_1L a_2L] + + represents the second-order sections of H(z): + + H(z) = g * product(k=1 to L) H_k(z) + = g * product(k=1 to L) (b_0k + b_1k*z^(-1) + b_2k*z^(-2))/(1 + a_1k*z^(-1) + a_2k*z^(-2)) +*/ + +function [s,g] = cell2sos(c) + if(argn(2)~=1) then + error("cell2sos: Wrong number of input arguments"); end - end - if (argn(1)==2) - d=c(1).entries; - if(length(d)==2) - g1=d(1); - g2=d(2); - g=g1/g2; - c=c(2:L); - else - g=1; + L=prod(size(c)); + k=1 + for i=1:L + if(type(c(i))~=17) + error('cell2sos: Cell contents must themselves be cell objects'); + end + end + gain_p = 0 + if length(cell2mat(c{1}))== 2 then + gain_vec=cell2mat(c{1}) + k=gain_vec(1)/gain_vec(2) + L=L-1 + gain_p=1 + end + s = zeros(L,6); + for i=1:L + if gain_p + s(i,:)=cell2mat(cll{i+1}) + else + s(i,:)=cell2mat(cll{i}) + end end - end - L=prod(size(c)); - s=zeros(L/2,6); - for i=1:2:L-1 - j=ceil(i/2) - b=c(i).entries; - a=c(i+1).entries; - b=b(:).'; - a=a(:).'; - b=[b,zeros(1,3-length(b))]; - a=[a,zeros(1,3-length(b))]; - s(j,:)=[b,a]; - end + if nargout < 2 then + s(1,1:3)= k * s(1,1:3) + else + g=k; + end endfunction + +/* +cll = {{[3 6 7] [1 1 2]} + {[1 4 5] [1 9 3]} + {[2 7 1] [1 7 8]}}; +sos = cell2sos(cll) // passed + +cll = {{1 2} {[3 6 7] [1 1 2]} + {[1 4 5] [1 9 3]} + {[2 7 1] [1 7 8]}}; +sos = cell2sos(cll) // passed + +*/
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